code: def test_series_instance(self):
      s = pdml.ModelSeries(
          [1, 2, 3, 4, 5], index=["A", "B", "C", "D", "E"]
      )
      self.assertIsInstance(s, pdml.ModelSeries)
  
      s = s[["A", "B"]]
      self.assertEqual(len(s), 2)
      self.assertIsInstance(s, pdml.ModelSeries)
  
file_path: pandas-ml/pandas_ml/test/test_series.py
imports: import numpy
  import pandas
  import sklearn.preprocessing
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 1 for calling the TestModelSeries obj's underlying member method code with example usage: obj.test_series_instance() without return types